1. Technical Field
The present invention relates to a polymer optical waveguide and a method of producing the same.
2. Related Art
Optical waveguides using polymer materials (polymer optical waveguides) have been developed as a means for optically transmitting signals within or between devices such as personal computers and mobile phones.
Optical waveguides are basically configured by a core through which light travels and a cladding enclosing the core and having a lower refractive index than that of the core. The following techniques, for example, for producing a polymer optical waveguide have been proposed.    (1) A method including impregnating a film with a monomer, selectively exposing a core portion to light so as to change the refractive index at the core portion, and adhering additional films to the film (selective polymerization method).    (2) A method including forming a core layer and cladding layers by coating, and forming a cladding by reactive ion etching (reactive ion etching (RIE) method).    (3) A method using photolithography in which a UV-curable resin obtained by adding a photosensitive material to a polymer material is exposed to light and developed (direct exposure method).    (4) A method using injection molding,    (5) A method including forming a core layer and cladding layers by coating and exposing a core to change the refractive index of the core (photobleaching method).    (6) A method of producing a polymer waveguide using a mold.
When a polymer optical waveguide and a planar light-emitting device or planar light-receiving device (hereinafter referred to as a light-emitting/receiving, device), such as a surface-emitting laser (e.g., a vertical cavity surface emitting laser (VCSEL) or a semiconductor photodiode), are combined to form a waveguide-type optical module, it is a common practice to form a reflective surface at its end.